Studies using CD8 immunohistochemical staining have shown that tumour-infiltrating CD8+ lymphocytes are favourably associated with patient survival in several cancers (i.e., breast, bladder, colorectal, esophageal, glioma, lung, melanoma, ovary, renal and head and neck cancers) [66,67,68,69,70]. Here, CD8A is linked to head and neck cancer.